I've implemented the basic functionality of Log.
I can now add, edit, and delete logs. I've implemented a rating system to track how much time I've spent on the task (available daily time, from 1 to 10), and how was my mood before and after the task.
I've also implemented suggestions for Area and Projects, so most of the times I won't have to type.
Adding a new log entry takes me about 5 seconds.
I'm now working on the design. I want to add graphs to visualize my logs.